1. Field of the Invention
The invention concerns a volume measuring and dosage device according to the preamble of claim 1.
2. Description of the Prior Art
Such volume measurement and dosage devices are already known in many versions and in the most varied applications. In practice they are mostly employed for the delivery of liquids out of supply containers, for the transfer of liquids and/or to mix liquids in defined proportions. For example, EP-A-96 088 describes a flask-cap piston burette, with which liquid can be withdrawn from a container by means of a cylinder-piston-valve-system, and delivered with a specific dosage. The actuation of the cylinder-piston system is achieved manually. The flow of liquid is alternately so obstructed, that suction out of the container and delivery through an outlet tube is alternately possible.
GB-PS-1,481,521 describes an arrangement with which numerous different liquids can be drawn up into one cylinder-piston-system and delivered again through a common outlet tube. The control of the liquid ensues by means of a slider-valve-system, by which numerous channels in the slider of the valve-system can be alternately connected to either outlet or inlet tubes.
The applicant's own EP-B-188 453 makes a device known for determination of liquid quantities, whereby the bottom of a cylinder is equipped with channels. These channels are led through the cylinder bottom without a blocking device, and finish as openings on its inside, whereby the end wall of the cylinder rests with a sealing fit on the cylinder bottom, in order to close off the openings. Through the relative displacement of the cylinder bottom, the openings in the cylinder bottom can be exposed or obstructed.
This known device is exceptionally suitable for analysis. However, the mechanical complexity for relative movement of the cylinder bottom and the cylinder wall is relatively high. Apart from that, the arrangement normally demands, for drive reasons, a fixed connection between the actuation device and the cylinder-piston-valve-device. In practice it can be desirable to design the arrangement in such a way that the actuation device can easily be separated from the piston and valve system, in order, for example, to connect cylinder-piston-systems with differing volumes onto the same actuation device (e.g. an electronically controlled motor drive.)
In addition, the device according to the previously described invention should be easy to dismantle, so that the cylinder and piston can be exchanged (e.g. for purposes of adjustment to differing volumes). The cylinder-, piston-, and valve-system should also be easily accessible and interchangeable for cleaning purposes.
Additionally, the operation of the valve system should be as simple as possible, as well as being able to be carried out both manually and with a drive motor.